Abstract: Well bore drill string shock absorber device for absorbing drill bit vibratory displacement shock, contemplating a pair of slidably, e.g. telescopingly, associated longitudinal elements, one of which is connectable to a drill string therabove and the other of which is connectable to a drill bit therebelow, such elements being interengageably interconnected for common rotation about a longitudinal, e.g. well bore, axis and for selectively limited relative reciprocal displacement longitudinally with respect to each other along such axis, and such elements together defining a shock absorber work chamber within longitudinal confinement wall portions thereof, e.g. an annular cylindrical chamber, of varying selective maximum and minimum operative longitudinal dimension and corresponding volume in dependence upon such displacement of the elements and in turn of such wall portions, and temporarily internally compressible and resilient shock absorbing means, e.g.